Log4j is an open source tool developed for putting log statements into your application. It was developed by the good people at More>>

Log4j is an open source tool developed for putting log statements into your application.It was developed by the good people at Apache's Jakarta Project.It's speed and flexibility allows log statements to remain in shipped code while giving the user the ability to enable logging at runtime without modifying any of the application binary. All of this while not incurring a high performance cost."
<<Less